1. After READER is plugged in, create a 'fonts' directory in the root directory of the READER. So the directory is READER\fonts
2. Go to Windows fonts directory and pick out the font you want to use. I'm using XP and in XP the font is in C:\Windows\Fonts. (same for Windows 7? Maybe other members can comment). Get a detailed view of the fonts.
3. The fonts have to be TrueType or OpenType and the family has to have 4 sets of them (regular, italic, bold, bold italic).
4. Suppose you want Georgia. Then copy the files georgia.TTF, georgiab.TTF, georgiaz.TTF, georgiai.TTF to READER\fonts

OK. I am still with you. Both the 950 and 350 are flashed. "font" folder created and the four Georgia fonts and four Segoe UI fonts copied to the folder.

I feel like I am getting closer.

One caveat. On Windows 7 when I went to the font folder, things went to a Control Panel type window and I could not see the Reader. After a couple of minutes I opened the Reader in a separate window that I put on one-half of the screen and the font folder on the other half of the screen and I was able to copy the font files to the Reader.

It's now been hours and hours trying to figure this out. It just shouldn't be this hard.

I don't have Windows 7 so I'm not sure what the Control Panel type window is for fonts. Go to Windows Explorer view.
Anyways, you should have in the READER the following files:
READER\fonts\georgia.ttf
READER\fonts\georgiab.ttf
READER\fonts\georgiai.ttf
READER\fonts\georgiaz.ttf

Go back and check out the change with a epub. Sometimes the font change doesn't happen and requires the reader to be turned off and on again, so to be on the safe side, do that.

Also the font change doesn't happen with every ebook. For example, it doesn't work with the Suze Orman or Harlan Corben samples in the Reader, or any of the free Google ebooks. I think it's because they have weird css coding. But it works with your own generated epubs, epubs that I've bought (notable ones are from Random House) and epubs from Gutenberg Project. I would test with an epub from Gutenberg project.

I've tested this and it works. Just be sure to reboot. The font change doesn't happen right away.

I have the fonts in the folder. I might have gotton things rights by accident. Is it true that once you open a book in one font, you can't change the font?

is this right????

No, I was able to disable the userstyle css and I also had other css files for different font to choose. The change doesn't happen right after the selection. I often had to reboot the reader (turn off and on).

Whenever you open a book, the reader creates a file named "style.css" in the epub subdirectory. When you change the font and then open the same book you had, it still uses the old style.css file. You have to force it to create a new style.css file, which will then change your font, by changing your css file to the font you want, open any other book, then re-open the book you were reading and the font will be changed.

Is it true that once you open a book in one font, you can't change the font?

No it's not true. However, if you already have an epub open and you use PRSPlus to choose a different one of your custom .css files, then you will need to open a second epub, close it again, then go back to the first epub before it will display the new font.